Top Five Free Web Page Accessibility Validators

It's a lot easier to incorporate accessibility into your site while designing it than than after coding is done, and it often pays to run your pages through an HTML validator. It's one of the most sure-fire ways to make certain that you haven't overlooked something crucial. In today's article, we're going to be looking at some freely available tools and services that you can put to good use on your own web pages.

What to Test

The W3C's Web Content Accessibility Guidelines (WCAG - pronounced as a word "wuh-cag") 1.0 consists of three priority levels that act as an industry standard. The first level, Priority 1, covers items on web pages that must be made accessible in order for individuals with disabilities to access the content at all. The second level, Priority 2, includes items on web pages that should be made accessible to allow a wider group of users to access the content. The third level, Priority 3, describes items on web pages that can be made accessible to allow the widest amount of individuals with disabilities to use the site. For more information about WCAG 1.0 visit the W3 web site.

Similarly, Section 508 of the United States Rehabilitation Act outlines the requirements for making federally-funded websites accessible to individuals with disabilities. The standards detail how different components of websites need to be designed to make the web content accessible. Under Section 508, the U.S. federal government has 16 standards that are used to define web accessibility. For more information about Section 508 visit the WebAIM Section 508 checklist.

A Few Beneficial Features to Look For

Besides knowing which standards to validate against, there are other factors that you may want to look for in an HTML validator tool. For instance, an error list is a good start, but does the tool also provide some suggestions for fixing the problems? Depending on how many pages you have to check, you may want to try to find a tool that supports batch or even site-wide processing; most online tools can only accept one page at a time. What kind of reports are generated? The level of detail can vary greatly. Can the tool simulate a text only view, without images, formatting, colors, or multimedia, so that you can determine if the page content is still intelligible?

Online Validators

The W3C Validator Service

If you're testing against the WCAG and your site contains only a few pages, a good place to start is the W3C Validator Service. It validates HTML, XHTML, SMIL, MathML, as well as other types of markup. The document can be submitted by URL, file upload, or by pasting the source code.

WebAIM's WAVE Tool

Rather than providing a complex technical report, WAVE shows the original web page with embedded icons and indicators that reveal the accessibility of that page. It also accepts pages by URL, file upload, or by source code. In addition to the Web service, the WAVE validator is also available as a Firefox toolbar and Dreamweaver Extension.

The HiSoftware Cynthia Says Portal

HiSoftware Cynthia Says validator service accepts a URL and identifies errors related to both Section 508 standards and/or the WCAG guidelines. You'll notice that the service will expose you to the underlying technology and the benefits of using HiSoftware's full-featured solutions for automated content compliance and web governance. A neat feature of this service is that it can emulate different browsers. They offer a full options Cynthia Says Tester as well.

University of Illinois at Urbana-Champaign Functional Accessibility Evaluator 1.1

University of Illinois at Urbana-Champaign FAE tool evaluates the functional accessibility of a single web page via URL. However, you have the option of registering for a free user account to gain access to these additional features:

Evaluate multiple pages via web crawling

Generate a Site-wide Report that identifies problem pages

Save reports in an account-specific Archived Reports list

It returns both Summary and Page reports.

Software Validators

HTML Tidy for Windows

HTML Tidy is an open source tool that is maintained by a group of volunteers at Source Forge. Originally written by a W3C member Dave Raggett, it not only assists with web accessibility by testing your markup against the W3C WCAG spec, but also validates and fixes HTML syntax errors, formats source layout, and performs conversion from HTML to XHTML, among other things.

It comes packaged with some HTML editors, including a free one called HTML-kit. It has a menu command to run the page source through HTML Tidy which presents the results in a split screen view. All the changes are listed in the messages pane. Here's the results from running an early version of this page through Tidy:

Firefox Accessibility Evaluation Toolbars

That was five, but here's an added bonus. There are several Firefox accessibility add-ons to choose from. One is based on the Illinois Information Technology Accessibility Act (iCITA) Implementation Guidelines for Web-Based Information and Applications 1.0 HTML, which incorporates elements of both the Section 508 and WCAG specs. You can download it here.

Some users have complained about excessive false positives as compared to the WAVE Firefox toolbar, while others are satisfied with it. I suggest trying both and see which works best for you.